1. Field of the Invention
The present invention relates to a hand-held tool for forming a rivet head on the plain end of a rivet used to join two or more plates or other structural members together and more particularly to such a hand-held tool embodying a construction and arrangement of parts for controlling the upsetting of rivet material to establish an effective load-bearing joint with the newly formed rivet head having a desired head dimension.
2. Description of the Prior Art
It is well known in the art to fasten two or more structural members togther by a riveted joint usually made up of one or more rows of rivets in a rivet pattern. The installation of a rivet requires hammering or otherwise upsetting the plain end of the rivet protruding from a rivet hole to form a rivet head which must tightly bear against the metal of the structural member surrounding the rivet hole. Power operated tools are used for impacting the preformed rivet head but a bucking bar of some sort is needed to form a shop head on the rivet. The present invention addresses a need for a readily controllable, hand-held tool to form a rivet head particularly in an operating environment of limited space otherwise prohibited to the use of automatic rivet machinery and power operated tools.
The hand-held tool of the present invention is particularly useful in the aircraft industry for cold riveting of aluminum or aluminum alloy rivets in locations generally not accessible to power operated tools. Additionally, the rivet head formed on the plain end of a rivet is controlled by the operation of the hand-held tool of the present invention can be used to ensure compliance with certain industrial standards in the aircraft industry that govern rivet adequacy. Under a visual inspection standard, the cold-worked rivet is examined to assess whether the end of the newly formed rivet head tightly bear against the metal surrounding the rivet hole and that the rivet head is uniformly thick. Under a more rigorous, or "zero tolerance" standard, the height and diameter of the newly formed rivet head are measured for compliance with an exact, "zero tolerance" head thickness and diameter standard. For example, a #5 rivet must have a head thickness which is one-half the diameter of the rivet shank diameter and a head diameter which are one and one-half the rivet shank diameter in order to satisfy the zero tolerance standard.
It is an object of the present invention to provide a versatile hand-held tool for forming a rivet head with a predetermined configuration on the plain end of a rivet.
It is a further object of the present invention to provide a hand-held tool for forming a rivet head compliant with rivet head standard of either the visual inspection standard or the zero tolerance standards.
It is another object of the present invention to provide a hand-held tool enabling a selection of parts suitable to establish a predetermined head thickness and selective to provide controlled or uncontrolled lateral spread of the deformed rivet material.